Auswirkungen einer Weißklee-Untersaat in Winterraps auf den Ertrag der Folgekultur Weizen

Summary

Due to the high nitrogen requirements, oil seed rape should be cultivated after rye-grass-clover mixtures (Böhm 2007). But in this case oil seed rape is in competition with wheat, because wheat has a high N-requirement as well. So, the crop rotation must be organized in another way, so that there is no competition between oil seed rape and wheat. In two-year field trials at the experimental farm of the Institute of Organic Farming (FAL) in Trenthorst the hypothesis was tested, whether oil seed rape with an undersown white clover is a better preceding crop to wheat compared to oil seed rape without underseed. Additionally, the yield was compared to “wheat after ryegrass-clover mixture”. The results showed a higher yield of wheat after oil seed rape with undersown white clover compared to the wheat after oil seed rape without underseed. Only in one year was the yield of wheat after ryegrass-clover mixture about 0.45 t ha-1 higher than the yield of wheat after oil seed rape with undersown white clover. Under the given conditions of location, the yield of wheat after “oil seed rape with an undersown white clover” is similar to that after ryegrass-clover mixture. So, an integration of oil seed rape in the crop rotation seems possible without a lower yield of wheat.